if i recall correctly, PhotoShop allows one to set up and measure the
density of a step wedge that can then be printed out on transparency
film. Will that do to calibrate? Or, why can't one just scan the b&w
negative and use the photoshop densitometer to make the measurements
and avoid building or buying anything else at all?
Roger
On 11 Oct 2009, at 7:06 PM, ADavidhazy wrote:
It is calibrated against a calibrated step wedge sold by Stauffer
(sp?)
andy
Roger Eichhorn wrote:
How do you calibrate it once you have it built?
A few years ago I ran into an EE friend who was returning to the
college from a purchasing expedition. He said that he was picking
up a "constant voltage source" -- alkaline batteries. It used to
require mercury cells, probably no longer available.
Roger
